存在主義是一種人文主義

...... 因此無所謂人性，因為沒有上帝 去創造這個概念，人赤裸裸地存在。他不是想像中 ( conceive )的自己，而是意欲 ( will )成甚麼才是甚麼；他存在之後，才能想像他自己是甚麼，這是在他躍進存在之後意欲的 ( what he wills himself to be after this thrust toward existence )，人除自我塑造之外甚麼也不是。 ( Man is nothing else but what he makes of himself. ) ”

— 沙特《存在主義是一種人文主義》


Atheistic existentialism, of which I am a representative, declares with greater consistency that if God does not exist there is at least one being whose existence comes before its essence, a being which exists before it can be defined by any conception of it. That being is man or, as Heidegger has it, the human reality. What do we mean by saying that existence precedes essence? We mean that man first of all exists, encounters himself, surges up in the world – and defines himself afterwards. If man as the existentialist sees him is not definable, it is because to begin with he is nothing. He will not be anything until later, and then he will be what he makes of himself. Thus, there is no human nature, because there is no God to have a conception of it. Man simply is. Not that he is simply what he conceives himself to be, but he is what he wills, and as he conceives himself after already existing – as he wills to be after that leap towards existence.

Man is nothing else but that which he makes of himself. That is the first principle of existentialism. And this is what people call its “subjectivity,” using the word as a reproach against us. But what do we mean to say by this, but that man is of a greater dignity than a stone or a table? For we mean to say that man primarily exists – that man is, before all else, something which propels itself towards a future and is aware that it is doing so. Man is, indeed, a project which possesses a subjective life, instead of being a kind of moss, or a fungus or a cauliflower. Before that projection of the self nothing exists; not even in the heaven of intelligence: man will only attain existence when he is what he purposes to be. Not, however, what he may wish to be. For what we usually understand by wishing or willing is a conscious decision taken – much more often than not – after we have made ourselves what we are. I may wish to join a party, to write a book or to marry – but in such a case what is usually called my will is probably a manifestation of a prior and more spontaneous decision. If, however, it is true that existence is prior to essence, man is responsible for what he is. Thus, the first effect of existentialism is that it puts every man in possession of himself as he is, and places the entire responsibility for his existence squarely upon his own shoulders. And, when we say that man is responsible for himself, we do not mean that he is responsible only for his own individuality, but that he is responsible for all men.